Workholding device



Dec. 18, 1923. mm fi 1 H. S. BERGEN WORKHOLDING DEVICE Filed Jupe 13. 1921 2 Sheets-Sheet 1 fi/JBBY 5 55126517 Dem L8 1923.

H. S. BERGEN WORKX' IOLDING-DEVICE Filed June 13 1921 2 Sheets-Sheet 2 w @m/Mw Patented Dec. 18, 1923.

that

HARRY S. BERGEN, F TOLEDO, OHIO.

WORKHOLDING DEVICE.

Application filed June 13, 1921. Serial No. 477,130.

points of support so that they engage the casting with substantially equal pressure.

16 Cast metal parts are not made absolutely uniform and are always subject to more or less warping and distortion during the process of cooling. For this reason it is impossible to construct a fixture for holding to a cast part during a machining operation which has more than three rigid supportin oints against which the casting is clampe wing to the flexibility of the metal in large thin castings three points of support are unsufiicient, as the piece cannot be held thereby sufiiciently rigid for machining operations. When individually adjustable supporting pins are employed in connection with the three rigid supporting pins it is very diflicult to so adjust them that the casting is engaged by each of them with the same pressure, and their adjustment requires considerable time.

Another object of this invention is to provide a work holding device having a plurality of adjustable supporting pins which may simultaneously be brought into engagement with the piece to be held.

Another object of the invention is the provision of means for so adjusting the several adjustable supporting pins that the casting is engaged by them with equal pressure. -Other objects and advantages will be apparent from the following description, in which reference is had to the accompanying drawings illustrating a preferred embodiment of my invention and wherein similar reference numerals designate similar parts throughout the several views.

In the drawings Figure 1 is a plan view of a work holding device embodying my invention, a substan tially annular scale housing casting being shown thereon;

the profiling cutter.

Figure 2 is a sectional view taken substantially on the line 22 of Figure 1; and

Figure 3 is an enlarged fragmentary sectional view taken substantially on the line 3-3 of Figure 1.

Referring to the drawings in detail, the base 1 of the work holding device is provided with suitable notches 2 to facilitate its attachment to a profiling machine. Proecting from the base are three substantially equi-distant rigid work supporting members.

3 against which the casting C to be machined is clamped by means of the adjustable clamping jaws 4. The end of each of the clamping jaws opposite to that engaging the casting rests upon a lug 5 which projects from the base, and a bolt 6 also projecting from the base passes through a slot 7 in each of the jaws 1 and is provided with a nut by means of which the jaw may be drawn downwardly to clamp the casting against the work supporting member 3. Owing to the fact that the jaw is slotted it may, when the clamping nut is loosened, be moved longitudinally out of engagement with the casting. An expansive spring 8 which surrounds the bolt 6 serves to hold the jaw in elevated position so that it may readily be moved into and out of clamping position.

The work holding device is also provided with a locating pin 9 adapted to engage a notch cast in the casting and with a slidable positioning plate 10 having a notch 11 adapted to engage a boss 12 which is formed upon the opposite side of the casting. The positioning plate is movable into engage ment with the boss 12 by means of a hand screw 13. r

In order to prevent the casting from springing during machining operations I have provided a plurality of vertically movable supporting pins 14, these pins being preferably located to support the portions of the casting which are to be engaged by If, for example, the casting is provided with bosses such as 15 at the points where it is to be profiled, the pins 1 1 are so located as to engage the casting substantially beneath the bosses 15. Each of the vertically movable pins 14: is urged toward its uppermost position by means of an expansive spring 16. When the casting is laid upon the pins the pins are forced downwardly and the springs 16 V are compressed until the casting rests upon the fixed supporting members 3. All of the pins Mare, however, in engagement with the lower side of the casting, regardless of any irregularities which may have occurred in the moulding of the piece or which are due to distortion during cooling. Each of the pins 14 is beveled at one side, as at 17, the beveled portion of the pin being engaged by a thrust member 18 which is adapted to be forced intoclamping engagement with the pin. It is one of the features of myinvention that a plurality of these thrust members may be simultaneously forced into engagement with the pins which they clampingly hold in place. At the upper side of Figure 1 I'have-shown a plurality of thrust members 18, 19 and 20 which are operated bya single hand wheel 21. As will be .apparent from an inspection of Figure 2,'the thrust members 18 and 19 are slidably mounted in grooveswhich are formed in the upper surface of'the base 1 and extend from theopenings'in which the pins 14 are mountedito "a larger opening 22 passing vertically through the base. Supported upon the'base above the opening 22 so that it is free to move laterally in all directions is a block 23 having a vertical opening through which extends a bolt 24, the upper end of which i's threaded into the hub-of the hand wheel 21 and the lower end of which is integrally formed with athree-sided wedge member 25. Then the 'hand'wheel is turned to the right the 'bolt'24 and the three-sided wedge member are drawn upwardly, thus forcing the thrust members 18, 19 and 20 outwardly into clamping engagement with thepins 14. Since the block 23, bolt 24 and wedge 25 are free, to move laterally in all directions, they form a fioating wedging device and the pressure exerted upon each of the thrust members '18, 19 and 120 will be substantially the same, regardless of whether or not the pins 14: engaged by the thrust members have been pushed downwardly to the same one tent by the casting with which they are engaged.

At the lower side of Figure 1 I have shown a slightly differentarrangement of supporting pins and clamping'thrust members. In this series the hand wheel 26 controls four pins. The lower end 27 of the bolt28 is a two-sided wedge member which, when the bolt is drawn upwardly byturning the hand 'wheel'26, forces'thethrust members 29 and. 30 outwardly in opposite directions. The ends of the thrust members 29 and 30, instead of engaging directlywith a pin 14, are beveled laterally, as at 31 and The beveled portion of the member 29 engages the rounded end 33 of a laterally extending thrust member 34, the thrust member 34 being arranged to clampingly engage a pin 14 which assists in supporting a bracket 35 groove, so that its end 33 may be swung in the direction of movement of the thrust members 29 and 36. Thebeveled end 32 of the thrust member 30 engages the rounded end 37 of a thrust member 38 which is substantially like the thrust member 3 1, the rounded end 37 being engaged with a'beveled portion of a short thrust member 39 which is similar to the thrust member 36,-the members 38 and 39'being adapted to clampingly engage supporting pins 14-. The bolt upon which the hand'wheel 26 is turned passes downwardly through a block 4L0, which, like the block'23, is free to move laterally in all directions. When, therefore, the hand wheel 26 is turned to drawthe twosided wedge member 27 upwardly, the thrust members 29 and 30 are forced outwardly, causing the members 342 and 38 to move sidewise and the thrust members 36 and 39 to be forced into clamping engagements with their supporting pins. When the 'endwise movement of the members 36 and 39 is-resisted by their coming intoclamping engagement with their pins, further movement ofthe members 29 and 30 forces the members 34land38 endwise into clamping engagement with their pins 14:. The pins 14:,which are clamped by the members 36, 39, 3i and 38 are thus clamped with substantially equal pressure.

ln'order to provide means for keeping the pins T l properly lubricated and to prevent dirt from getting into the openings in which they are mounted, I have provided a stuffing box all for each'of the pins which con tains a ring of fibrous material 12 that is saturated with oil. The stuffing boxes 11 are held in place by means of screws 42.

The location. and arrangement of the thrust members and the operating' wedges and hand wheels therefor will, of course, depend upon the nature and shape of the casting to be held in place. It is obvious that the number of laterally extending thrust members, such as 3 1 and 38, which maybe operated by a longitudinally extendingseries of thrust'm-embers having adjacent beveled ends, is' not limited to one'for each set of longitudinally movable members.

lVhile it will be apparent, therefore,-that the illustrated embodiment of my invention hereindisclosed is well calculated to adequately fulfill the objects primarily stated, it is to be understood that the invention is susceptible to variation, modification and aavaoec change within the spirit and scope of the subjoined claims.

Having described my invention, I claim:

1. In a device of the class described, in combination, a plurality of self-positioning supporting members, and means for simultaneously clamping said supporting members in supporting position, said clamping means comprising a plurality of clamping members and a floating wedging device for forcing said clamping members into engagement With the supporting members.

2. In a device of the class described, in combination, a base, a plurality of supporting members thereon, resilient means for yieldingly holding said supporting members against an object to be supported and thereby positioning said supporting members, and means for simultaneously clamping said supporting members in supporting posi tion, said clamping means comprising a plurality of clamping members and a floating Wedging device for forcing said clamping members into engagement With the supporting members.

3. In a device of the class described, in combination, a base having an opening therein and a plurality of channels radiating from said opening, a plurality of selfpositioning supporting means located at the ends of said channels, a thrustmember lying in each of said channels, a wedging device in said opening, and means for forcing said Wedging device into Wedging engagement With the ends of said thrust members and thereby forcing said thrust mem bers into clamping engagement with said supporting means.

4. In a device of the class described, in combination, a base having an opening therein and a plurality of channels radiating from said opening, a plurality of selfpositioning supporting means located at the ends of said channels, a thrust member lying in each of said channels, a Wedging device in said opening, and means for forcing said Wedging device into Wedging engagement with the ends of said thrust members and thereby forcing said thrust members into clamping engagement With said supporting means, said Wedging device forcing means comprising a member engageable With said base and freely movable thereon, a bolt passing through said member, and a hand Wheel threaded onto said bolt.

5. In a device-of the class described, in combination, a base having an opening therein and a plurality of channels radiating from said opening and also having a plurality of channels extending laterally from said radiating channels, a Wedging device located in said opening, thrust members lying in said radially extending channels, said thrust members having beveled ends terminating adjacent the ends of said laterally extending channels, clamping members lying loosely in said laterally extending grooves and having ends engaging the beveled ends of said thrust members, clamping members lying in said radially extending channels and having beveled ends engaging the ends of the first said clamping members, self-positioning supporting members mounted at the ends of said radially extending and laterally extending channels, and means for forcing said Wedging member into Itavedging engagement with said thrust memers.

6. In a device of the class described, in combination, a base having radially extending channels therein and laterally extending channels connected with said radially extending channels, self-positioning supporting members at the ends of said channels, clamping members lying in said channels, and means for forcing said members into clamping engagement with said supporting members.

7. In a device of the class described, in combination, a plurality of longitudinally aligned thrust members said thrust members having their adjacent ends oppositely beveled, and a thrust member extending substantially perpendicular to the first said thrust members and adapted to be operated thereby, the end of the last said thrust member being engaged by the beveled ends gf said longitudinally aligned thrust memers.

HARRY S. BERGEN.

Witnesses HARRY ERNSBERGER, FRANCES DOYLE. 

